PTFE packing ring is a kind of sealing ring made of PTFE fiber as the main material, woven into cloth (or braided into packing), impregnated with PTFE emulsion, molded by mold, and sintered. This kind of sealing ring has the advantages of strong sealing, high pressure resistance, and strong corrosion resistance. The expanded graphite packing ring is continuously wound by expanded graphite paper and compressed in a mold. It has all the excellent properties that a good sealing material should have. When used alone or in combination with other fillers, it is especially suitable for static sealing parts under high temperature and high pressure conditions. It can be used safely in all media except aqua regia and strong oxidizing acid.